This invention relates to a container lid having a safe open edge after a central plate portion has been torn off along a score or tear line using a finger tab.
Easy-opening type container lids have been required in the past so that the containers can be easily opened without using any particular tools such as can openers. To satisfy this requirement, the container lids have a tear tab fixed to a central plate portion defined by a tear line, and the lid is removed by pulling up on the tab. However, after the plate portion is torn off, the sharp edge remaining on the side of the container presents a potential hazard to the user. Therefore, various attempts have been made to leave the open edge as safe as possible.
A prior art lid construction, as disclosed in Japanese Patent Publication No. 44077/1972, is shown in FIGS. 9 and 10 of the accompanying drawings, wherein a metal lid for a cylindrical container 106 comprises a center panel 101, a surrounding vertical wall 102 integral therewith, and a U-shaped bead 103 formed inside the vertical wall and extending inwardly in a direction substantially parallel to and spaced above the center panel. A tear line 105 completely encompassing a removable portion 104 of the center panel is disposed below the bead 103 so that when the portion 104 is removed the sharp edge formed on the cut line is positioned more radially outwardly than the bead 103 to prevent hurting the fingers of the user.
To open such a metal lid construction the head end 108 of a pull tab 107 fitted to the removable panel 104 is raised up and the tip portion 109 thereof is pushed downwardly to initially sever the tear line 105. The tab 107 is then further pulled upwardly to remove the panel 104 as a whole. When the tip portion 109 of the tab breaks the tear line 105 the applied force also pushes down the annular lip 110 below the bead 103, however, and the sharp exposed edge is no longer protected or shielded by the bead 103 and may thus injure the fingers of the user.
Further, when the tab 107 is pulled up to remove the panel 104 as a whole, the edge around the panel will be caught by the bead 103 because the tear line 105 is positioned more outwardly than the inner peripheral edge of the bead. As a result, the bead 103 and the lip 110 therebelow are bent upwardly to thus cause the same problem described above and render the container dangerous when handled.